Why doesnt this engine exist?

[scottzg]

It seems to me that the ultimate combination for a powerful/fun/economical engine would be to have a 1.0L 4 cyl supercharged engine with a burly crank, rods, etc.

It could be tuned very simply; change the size of the compressor wheel and have a flexible ecu.

It would get excellent economy, 1L displacement with more on demand.

It would suit sports cars nicely; very lightweight.

Off boost (lack of) power shouldnt be too horrible, you'd only see it at low rpms in 1st gear, before the supercharger is boosting, and a low 1st gear could combat that.

Additionally, that low displacement could rev fantastically if built for it....

So, why doesn't anyone make it?

[THAWA]

Didn't audi do something similar back int eh day. they used like a 1.8l with a big turbo and made more than 1000hp or someting. I don't qui8te remember all the specifics though.

[scottzg]

That's kind of different. That is a f1 engine. bmw made one using an m10. It has no bottom end and would be undrivable at low rpm. It also requires like, a billion octane gas. My idea takes advantage of the characteristics of a supercharger to make a daily driven engine.

[evolutionmovement]

Marketing is one concern, but a big one would be making a light enough vehicle that passes safety and, once again, is marketable (at least in this country). Look at how hatch backs today weigh in at 2700lbs. That's as much as my wagon. You would still need high octane to run any decent boost and manufacturing it would be expensive with the marketability problem. A bigger engine could be made cheaper and sold for more. Look at the premiums car makers charge for bigger engines over smaller ones. Does a V8 really cost the price differential they charge over the V6? Of course not, and generally speaking the more expensive the car, the greater the profit margin. A 1-litre car would have to be sold for cheap if at all and the competitive market combined with small margins would kill any such business proposal before it made it past a drawing.

It would also likely suffer from reliability issues due to the higher stresses and the fact that it would have to be thrashed to get it to move the car. It might be great in a race car where the weight would be low, but then fuel concerns aren't as much of an issue so half the point is moot.

Have you ever heard of the BRM V16 from the late forties? It was a 1.5 litre supercharged engine that revved to 12000 rpm back when most race engines barely pulled 5000. Amazing engine too far ahead of its time.

Steve

[BAC5.2]

Boost doesn't make for good gas mileage. Period. More air means more fuel. Boost is similar in fuel consumption terms as a larger engine.

Look at GM. The Z06 Corvette gets almost 30mpg on the highway. That's better than my SS on the highway. And it's almost triple the displacement.

A small engine wouldn't be as economical (for the producer) and wouldn't be as economical (for some consumers). It would go great for the daily driver, but would it be able to contend with a Honda Insight (the 2004 winner for best fuel economy in a production car)? Unlikely. Would you expect the Big 3 to produce it? No.

When your muscle head fanatic can get 30mpg on the highway out of a 405horse SBC in a Corvette, why would they want to drive around in a 1L car that get's the same mileage at 80mph?

It wouldn't be feasable to have a gear ratio short enough to take advantage of the honda-like bottom end, yet tall enough to pull good numbers on the highway. Remember, SC's are ALWAYS boosting on the highway (unless you run something like an Eaton which has a bypass setup, but even then there is a very noticeable parasitic draw from the blower itself).

I know I wouldn't drive a 1L car that get's the same milage as my car, but is pushing more than twice the boost.

[THAWA]

Doesnt the z06 have some type of engine management that allows it to only use x amount of cylinders or something like that?

the big 3 can suck my balls btw, which is one of the reasons I'm driving a subaru

I know I wouldn't drive a 1L car that get's the same milage as my car, but is pushing more than twice the boost.

why not?

[BAC5.2]

1/3 of the Big 3 owns almost 1/4 of Subaru. You've surely heard the term SAABaru, or seen that Subaru concept with the vagina on the front of it.

Why not? Well, I like to be able to get more than 100,000 miles out of a car without having it blow up, and I'd rather not use 10 million octane gas. The internals are only as good as the weakest link, and the head is still bolted to the engine. Bolts break and headgaskets blow.

[scottzg]

I was thinking more in line with the SC in the SC mr2. the blower is on a clutch type system that is activated by the ecu.

Idle- no rotation at all.
start moving- turn on SC
rolling along- no rotation
over 65mph- on boost

A tiny engine at idle and on the fwy. (It only takes 20 hp to keep you moving at 70mph)
I think it's reasonable to say that peak output on forced induction cars is more dependant on the number of cyls than the displacement of each cyl. With that in mind, i think my proposed engine could comfortably make 200 hp on premium gas and have the power delivery characteristics of a 2.8L v6. Lag would be minute since its a sc.

Why would stresses be so high? The bottom end pieces would simply resemble those of a larger engine, temp per psi of boost would be lower than a turbo because there is no intake passing through the exhaust manifold (know what i mean?)

Steve is right, marketing and cost per unit would be higher, but i would think that mass production (sooo much tunability, you could run every subie or mazda made on this one engine for example) could take care of production costs, and the interest generated by a new engine type would help the marketing.

[BAC5.2]

You aren't at idle on the freeway though, you are cruising.

And at partial throttle, it takes a higher RPM to make the same power (under WOT, you might make 180lb-ft at 2800 RPM's, but cruising at 75mph at 2800RPM's you are probably only making around 15 or 20). Since an SC is dependant on engine revoloutions, you are spinning the shaft at a speed proportional to the crank RPM. You are on-boost unless the ECU releases the clutch, in which case you will need to rev to a higher RPM to acheive the same power, the change in RPM will engage the clutch and start boosting again.

Imagine the following. You are cruising at 70mph making 20hp under boost. You cut boost, you are no longer going to be making enough power to sustain 70mph without more air and fuel. You compensate for the lack of boost with more throttle.

You'd be in a constant state of force-fed indecision. Does the ECU boost or not? If it does, you are wasting fuel, and if it doesn't you are wasting just as much fuel because you STILL have to make those 20hp under cruise conditions.

Peak output on FI cars (SC cars) is dependant on engine RPM, and completely (read, COMPLETELY) independent of the number of cylinders or total displacement. On Turbo cars, it has EVERYTHING to do with the amount of exhaust gas.

The air going into the plenum is STILL heated. That's what happens when you compress air, it get's hot. That's why you need an intercooler even on an SC car. Air gets hot. With such a small engine, and such high RPM requirements to attain power, the throttle response between hitting the gas and actually getting more air into the engine would be WORSE than turbo lag.

Plus, a clutch style SC is just asking for more things to break and require replacement. The best possible SC method would be a Whipple charger style compressor, as they ALWAYS make boost to a certain level. Very little lag, but with the downside of frying an engine.

The cross-use idea isn't a very good one. Mazda is a product of Ford, and Subaru is a partial product of GM. You really think that if FORD develops an engine, GM is going to allow a company they own a part of use it? No. And do you think Subaru would give up the one peice of heritage it's got going for it (the Boxer engine) just to make use of a powerplant that isn't as reliable as the current engines? Nope.

There is no such thing as a perfect engine. Every setup has it's downfalls.

[scottzg]

You aren't at idle on the freeway though, you are cruising.

And at partial throttle, it takes a higher RPM to make the same power (under WOT, you might make 180lb-ft at 2800 RPM's, but cruising at 75mph at 2800RPM's you are probably only making around 15 or 20). Since an SC is dependant on engine revoloutions, you are spinning the shaft at a speed proportional to the crank RPM. You are on-boost unless the ECU releases the clutch, in which case you will need to rev to a higher RPM to acheive the same power, the change in RPM will engage the clutch and start boosting again.

You would still be using less than the 1L's capability, so you give more throttle, ecu senses it, and engages SC. Back off throttle to cruise, and ecu takes off SC. Like an automatic tranny.

Imagine the following. You are cruising at 70mph making 20hp under boost. You cut boost, you are no longer going to be making enough power to sustain 70mph without more air and fuel. You compensate for the lack of boost with more throttle.

You'd be in a constant state of force-fed indecision. Does the ECU boost or not? If it does, you are wasting fuel, and if it doesn't you are wasting just as much fuel because you STILL have to make those 20hp under cruise conditions.

Throttle is depressed over, say, 60%, then SC kicks in. Under, then no. So the engine is throttled as it approaches cruising speed, with SC running. Reaches 65 and driver lessens throttle, and SC is taken offline. Later, driver wants to pass, floors it, SC is reengaged, burst of accel, and goes on by.

Peak output on FI cars (SC cars) is dependant on engine RPM, and completely (read, COMPLETELY) independent of the number of cylinders or total displacement. On Turbo cars, it has EVERYTHING to do with the amount of exhaust gas.

true, independant of displacement, but you're wrong about the number of cyls. If i have more smaller cyls, then i can rev higher, i have more spark per unit of air/fuel mix, and the combustion is faster because the expanding cyl is giving less volume for the mix to expand into. Ever wonder why Ferarris have 3 litre v12's instead of a 3 litre 4cyl?

Come to think of it, you're wrong about it having nothing to do with displacement too. More displacement = less boost to get the same volume of air. Less boost= less heating. And there is a limit to how much you can cool your intake charge and have a usable engine.

The air going into the plenum is STILL heated. That's what happens when you compress air, it get's hot. That's why you need an intercooler even on an SC car. Air gets hot. With such a small engine, and such high RPM requirements to attain power, the throttle response between hitting the gas and actually getting more air into the engine would be WORSE than turbo lag.

SC-ing heats air less than a turbo. I'm not considering making huge power numbers. Your own car doesn't come with an intercooler.

Plus, a clutch style SC is just asking for more things to break and require replacement. The best possible SC method would be a Whipple charger style compressor, as they ALWAYS make boost to a certain level. Very little lag, but with the downside of frying an engine.

yea, it is more complicated.

The cross-use idea isn't a very good one. Mazda is a product of Ford, and Subaru is a partial product of GM. You really think that if FORD develops an engine, GM is going to allow a company they own a part of use it? No. And do you think Subaru would give up the one peice of heritage it's got going for it (the Boxer engine) just to make use of a powerplant that isn't as reliable as the current engines? Nope.

you missed my point. My point is that all Mazda and subaru cars could be powered by different iterations of this same design, as Subaru already does with the ej series.

[BAC5.2]

You would still be using less than the 1L's capability, so you give more throttle, ecu senses it, and engages SC. Back off throttle to cruise, and ecu takes off SC. Like an automatic tranny.

That wasn't my point. My point was that you'd be forced to rev at insane RPM's to maintain speed. You'd accelerate under boost, and then the SC would shut of at partial throttle. But in order to maintain that 20hp output it would have to be done at a higher RPM. If you have a 1L engine, there's no way it's going to make power off-boost at any reasonable RPM. Look at the Honda Insight. It is powered by a 1.3L engine. Off-e-help, that little bugger must pump very quickly to maintain speed. It makes less than 75hp off of e-power, and it's at 13:1 compression, the limits of 94 octane. You really mean to tell me that in any reasonably geared car, a 1 liter engine built for FI (read, low compression) will perform acceptably off-boost to cruise on the highway? Have you ever driven one of these Hybrid cars? They are almost dangerous on the highway.

Throttle is depressed over, say, 60%, then SC kicks in. Under, then no. So the engine is throttled as it approaches cruising speed, with SC running. Reaches 65 and driver lessens throttle, and SC is taken offline. Later, driver wants to pass, floors it, SC is reengaged, burst of accel, and goes on by.

You will easily reach the limits of what 60% throttle can do off-boost in a low compression 1 liter engine.

true, independant of displacement, but you're wrong about the number of cyls. If i have more smaller cyls, then i can rev higher, i have more spark per unit of air/fuel mix, and the combustion is faster because the expanding cyl is giving less volume for the mix to expand into. Ever wonder why Ferarris have 3 litre v12's instead of a 3 litre 4cyl?

Come to think of it, you're wrong about it having nothing to do with displacement too. More displacement = less boost to get the same volume of air. Less boost= less heating. And there is a limit to how much you can cool your intake charge and have a usable engine.

Boost from a supercharger is solely dependant on engine RPM and ratios. An SC doesn't care if you are a 4cylinder or a V10. All it cares about is how fast it's input shaft is spinning. 13psi is 13psi is 13psi. Through a larger engine, the same amount of artificial aspiration is going to be split among more cylinders. Now manifold pressure is different. 13psi in the manifold is different than 13psi off of the turbine (how I was speaking). A turbo doesn't become more efficient when you bolt it to a larger engine. If it pumps out 13psi MAX before it becomes inefficient, then that's the maximum it will efficiently put out reguardless of the engine it is bolted to. If you hooked up the VF11 from our SS to a Dodge Viper, it's going to push the same amount of boost off of the turbo as it does in our car. 13psi in the manifold of a Viper is a LOT different than 13psi in the manifold of an EJ22.

Ferrari uses 3.4L V8's because they are dual overhead cam and can pump out a shit ton of ponies in the upper rev range. They make butt for torque (in relation to HP). I'm really not sure why you brought up the point of Ferrari's or small displacement, multi cylinder engines. But to answer your question, no, I never wondered why Ferrari uses those engines.

SC-ing heats air less than a turbo. I'm not considering making huge power numbers. Your own car doesn't come with an intercooler.

Not really. With an SC, there is a lot more friction going on. In a Turbo, the exhaust gas is independent from the intake charge. The exhaust simply runs near it. Your right, my car doesn't come with an intercooler. Name one SC car running the same boost that doesn't. The Nissan Xterra SC runs slightly LESS boost (8 pounds flat), and has a decently sized SMIC.

For a 1L engine, you aren't talking huge power numbers, but you ARE talking huge boost numbers.

you missed my point. My point is that all Mazda and subaru cars could be powered by different iterations of this same design, as Subaru already does with the ej series.

Ahh, your right. I did miss your point.

Platform sharing isn't new. Take Nissan for example. The Maxima, Altima, 350Z, G35, FX35, Pathfinder, Murano, and probably a few more I am forgetting all use the exact same VQ35DE engines with varying tunes. If it's got a 3.5L V6, and it's a Nissan, it's the same as any other new 3.5L V6 powered Nissan.

[evolutionmovement]

Look at the 4cyl supercharged engine in the SLK - its a universally acknowledged dog with greater displacement.

There are a few reasons for the Ferraris being 3.0 12 cyl. One was engine formulas at the time for racing which was maxed at I believe 1.5 litres. This displacement was deemed too small for road cars and rose as far as they could stretch the original Colombo design until they moved to the larger Lampredi block. Ferrari was a fan of the smoothness of the Packard V12 and so wanted it for his car. In racing, more cylinders are less stress for high speed running due to less power strokes/cyl/revolution which was a big contributer to Ferrari's excellent reliability under race conditions.

There's also the status of a 'V12' that makes it sound superior to lesser engines, so marketing again. But that's also because more cylinders are more expensive to manufacture. Look at Mercedes-Benz again where they offer a V12 and a V8 with no performance improvement from the V12 (actually, the V8-powered SL is a better performer).

Superchargers are precision devices and so will the necessary strong components for this 1-litre. Balancing, Q/A, and materials will all cost extra. I'd bet a larger unstressed V6 (like Hyundai) would be cheaper as it wouldn't require such expensive manufacturing tolerances yet due to its size would make a lot more torque.

The best bet would be a displacement-on-demand type system mated to a CVT for what you're looking for.

Steve

[BAC5.2]

D-O-D is what gives the Z06 it's 30mpg on the highway. Mate that with a subteranian 6th gear, and you are cruising at 80mph at under 2000 RPM's.

[evolutionmovement]

Exactly. I want D-O-D diesels with particulate traps running low-sulfur fuel mated to nice manuals (for me) or CVTs (when they get them reliable enough to handle the torque). It would kill any hybrid for durability, weight, cost, reliability, mileage, and maybe even environmental responsibility.

Or a steam engine, direct drive, running on alcohol I ferment in my spare room.

Steve

[THAWA]

1/3 of the Big 3 owns almost 1/4 of Subaru. You've surely heard the term SAABaru, or seen that Subaru concept with the vagina on the front of it.

I'm more than aware of that and thats part of thew reason they can suck it.

Why not? Well, I like to be able to get more than 100,000 miles out of a car without having it blow up, and I'd rather not use 10 million octane gas. The internals are only as good as the weakest link, and the head is still bolted to the engine. Bolts break and headgaskets blow.

You realize how strong an ea/ej closed deck is right? I'm sure you've read about people throwing hella boost at one and it did fine right? Also its not all about boost. You can inject shit to lower the amount of octane and increase power and, with the correct tuning, mileage

[evolutionmovement]

Our engine is even more expensive than an inline. This would be a very costly engine and while it may be interesting, the fact remains that it would be much more cost effective and broadly acceptable to do some larger N/A or low boost alternative. Small engines are only economical at low rpms anyway. A big loping engine with enough torque to move the car with low rpms can be more economical than a small engine running high rpms and especially with boost added. To simplify - an engine a third the size running three times as fast as a big engine will consume the same amount of fuel.

Steve

[BAC5.2]

You realize how strong an ea/ej closed deck is right? I'm sure you've read about people throwing hella boost at one and it did fine right? Also its not all about boost. You can inject shit to lower the amount of octane and increase power and, with the correct tuning, mileage

I was saying I wouldn't drive a boosted 1L engine. I wasn't saying anything about the integrity of the EJ.

Would you drive a 1L 4cylinder pushing anything over 20psi (which it would have to do to make any reasonable power to compete with anything on the market) on pump gas?

I sure as hell wouldn't, but then again, I'm accustomed to keeping the internals of my engine, inside my engine.

[THAWA]

Why do you think it's impossible to drive a car with more than 1bar on 91 octane? Are you forgetting that people are doing this daily on turbo legacies? I do believe their internals are all still internal.

What I was meaning to say was that you can run hella boost with a closed deck engine.

and yes I would drive it if it had good accelleration.

[evolutionmovement]

There's no way you could optimize power on lower octane. Ignition would have to be retarded or some other source of stabilization added to reduce combustion temperatures. There's also the long term reliability question - if the engine's walking a fine line on detonation, what happens with some minor hotspot in the combustion chamber? It just would not be a suitable engine for a road car.

Steve

[THAWA]

which is why I previously suggested injection something to help with that.

[evolutionmovement]

But does that sound like a practical every-day set up? An average car's lucky to have its oil changed regularly.

Steve

[azn2nr]

i was under the impression that sabb was strugling with getting an engin for their new small car so they "teamed up" with subau and that FHI still owned subaru completly

[BAC5.2]

And 1 bar is a lot different from 20psi (5.3psi to be exact). A lot can happen with that 5.3psi, ESPICALLY on a smaller engine. Less material means less margin for error in production. You could make a toothpick that could support a house, but would you want to?

1 bar can be done mostly safely on the stock ECU. More than that, and you are pushing what a stock ECU could acclimate itself to. You'd need standalone which would need dyno tuning every so often to keep running on pump gas without knocking so bad you wake the neighbors.

Like Steve said, an average car doesn't get it's oil changed at even intervals. It is simply not a practical solution.

Steve is with me on this one, right?

[evolutionmovement]

GM owns Saab 100%. GM owns ~20% FHI.

They wanted a smaller car for Saab to capitalize on the Euro craze of cut-price premium nameplates that they think is going to be big here. Developing a unique car would be time consuming, expensive, and likely not as good as the Subaru platform.

Steve

[BAC5.2]

i was under the impression that sabb was strugling with getting an engin for their new small car so they "teamed up" with subau and that FHI still owned subaru completly

No. GM owns SAAB almost completely, at least the majority stock holder. GM has an 18% stake in Subaru. GM has an influence if FHI want's to take it, but they could walk and pick up any other of the major manufacturers worldwide if they wanted to.

FHI is a hot commodity, that's why GM only own's 18%. If FHI was struggling, then GM would own a good bit more.